A kind of preparation method of valve seat powder metallurgy

Abstract

The invention discloses a method for preparing powder metallurgy of a valve seat. The method includes: the valve seat is made of following raw materials, by weight, 0.4-0.6% of nickel, 0.2-0.3% of carbon, 0.2-0.4% of manganese sulfide, 0.2-0.3% of vanadium, 0.6-0.8% of graphite powder, 0.1-0.2% of chrome, 0.3-0.4% of silicon, 1-2% of performance additive, 10-20% of copper, and the balance iron; via adding the performance additive, superfine powder is provided in the mixed raw materials and can fill in seams among large granules, so that density of the mixed materials is improved; main ingredients of the superfine powder include nano potassium feldspar powder and calcium stearate, and the novel performance additive is obtained via agent like silane coupling agent, physical properties like abrasion performance of prepared products is further improved; and polyethylene vinyl acetate and liquid paraffin serving as lubricating agent are added in the performance additive, so that effect of the performance additive under mixed compression is strengthened, the strength of compaction of power metallurgy structural members is greatly improved under same compression force, combining shape and hole shape of the raw material granules is changed, and problem about generation of crack is solved basically.

Description

technical field

[0001] The invention mainly relates to a powder metallurgy preparation method of a valve seat, which belongs to the field of casting. Background technique

[0002] With the continuous development of my country's economy, powder metallurgy structures are used more and more widely. As a near net shape technology, powder metallurgy has great economic advantages in the production of structural parts and other parts with large batches, high dimensional accuracy and high processing costs. However, there is a weakness in powder metallurgy structural parts: the compact strength of the product before sintering is very low, which leads to cracks easily appearing during the forming and handling process, and cannot be detected during the manufacturing process. This is a fatal defect in some applications such as key parts of automobiles, which leads to the application of powder metallurgy structural parts only to low- and medium-risk stress-bearing parts, and the scope o...